The teenager died on Friday night after reports of a brawl in Kurunjang, on the western outskirts of the Victorian capital, shortly after 7pm.
A 15-year-old boy was yesterday charged with murder over the incident, and today, police arrested a 22-year-old from Harkness over the incident after he was released from hospital.
Officers are interviewing him, but as of 5pm he has not been charged with any offence.
People living nearby the scene of the brawl said they had heard someone begging for their life.
“It’s just this time of year and hearing someone’s final begging for their life, I guess, it’s just horrible,” one neighbour said.
Police believe the alleged victim knew the 15 and 22-year-old and that it was a targeted incident.
Anyone with information about the alleged murder is urged to contact police.